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Hesitation on take off/changing gears

Hey everyone,

I've just noticed an issue where my N15 seems to hesitate for a second or so and then begin to build up speed/revs when taking off and also when shifting ie. from first to second or second to third. It seems to be a bit random when it occurs, however when taking off in first gear it will happen around 2,000 rpm, and from second to third is around the same.

I'm wondering whether anyone has experienced this and can shed some light onto what/where I should be looking at?

Following on from this, I have done a bit of research online with people have similar problems, and a lot of the suggestions said look at the air flow meter. I pulled the plug off of the air flow meter last night and tried to take it for a drive and it ran terribly and refused to hold a steady idle. Upon plugging it back in it ran much smoother, however still had this issue of hesitating upon acceleration and changing gears. I have also checked for any air/vacuum leaks and cannot hear or see any potential leaks/cracks in hoses etc. Unsure where to go from here!

Following on from this, I have done a bit of research online with people have similar problems, and a lot of the suggestions said look at the air flow meter. I pulled the plug off of the air flow meter last night and tried to take it for a drive and it ran terribly and refused to hold a steady idle. Upon plugging it back in it ran much smoother, however still had this issue of hesitating upon acceleration and changing gears. I have also checked for any air/vacuum leaks and cannot hear or see any potential leaks/cracks in hoses etc. Unsure where to go from here!

It drives fine all the way through the Rev range? Fine even over 5k rpm?

Yeah mate, it has occurred again today and taking note of the rpm at which it happened it was more around 1,500 rpm. This was once again taking off in first and shifting from first to second or second to third. After this hesitation the engine seems to pick up again and yes it will drive fine all the way through the rev range. I'll take it up to 5k+ tonight and see if that causes anything to happen.

EDIT: Took the car up to 5k rpm and beyond in both 1st and 2nd gears, didn't seem to have an issue after 5k rpm. I can however get the problem to occur every time now. In say 2nd or 3rd gear, if I accelerate from around 1,000-1,250rpm the car will just have a flat spot/hesitstion as it SLOWLY builds up the revs to 1,750-2,000rpm and then will appear to run and accelerate as usual. Wondering whether the AFM hot wire could be dirty? Might just clean that tomorrow regardless. My mechanic (without seeing the car) also suggested the ignition coil, however I believe these are located within the distributor? If that is the case then it should be okay; I replaced the distributor only a couple of months ago as my original was leaking oil internally.

Last edited by SLO015; 05-12-2017 at 07:24 PM.
Reason: More info added

The ignition coil isn't inside the distributor.
From memory there should be a 5th spark lead to the distributor that goes to your ignition coil nearby.
Don't think it's a common issue for them to fail, but worth a try. Should be able to get one from a wreckers.

I have a feeling it is mate.. there most definitely isn't a 5th lead from the dizzy to the coil. On my dizzy, there are only four leads from the dizzy to the engine and that's it. I'm going to clean the AFM this afternoon and see how that goes. From there I'm not sure what would be next to look at though!

I have a feeling it is mate.. there most definitely isn't a 5th lead from the dizzy to the coil. On my dizzy, there are only four leads from the dizzy to the engine and that's it. I'm going to clean the AFM this afternoon and see how that goes. From there I'm not sure what would be next to look at though!

I'm not familiar with GA's.
Would be an expensive distributor cap if it was inside!

The dizzy was actually quite cheap haha. I think it was $150 or something like that?

I've solved the problem by the way... long post ahead. So I pulled the spark plugs this morning to have a look, and the tops (as in above the threads) were covered in oil. I assumed that this was due to the spark plug tube seals being knackered, so decided to source some, plus a rocker cover gasket. As it turns out, the N15 as it has a plastic rocker cover, does not have a spare part listing for the tube seals as they are apparently non-serviceable. So taking to the internet, I found that some American guys have encountered the same problem yet got around it by using an N14 (I think they call them B13's; Almera I believe??) rocker cover which is aluminium. Although this is a minor difference, funnily enough the spare parts stores can source a seal kit which includes the rocker cover gasket and the spark plug tube seals. So I ordered one of these, and set off to the wreckers to grab myself an N14 rocker cover. The gasket kit is expected to arrive tomorrow, so all going well I will fit it all up and be sorted in no time. I have installed the new spark plugs and the hesitation is completely gone. I haven't driven too far however just so the new plugs aren't destroyed by the oil leaking down the tubes.

If it's of any benefit to anyone, I can take some photos of the rocker cover swap and document any issues that I have with fitting it. Let me know!

Figured I'd make a bit of a post on this process regardless; it may just help someone in the future!

Anyways; the photo below shows the gasket kit that I was supplied (by Repco). This was ordered to suit an N14 with a GA16DE engine.https://imgur.com/EoJVG8f
This kit cost me around $50 trade, but retail was $114. This I thought was quite excessive but it does include the rocker cover gasket, the four spark plug tube seals, an oil cap seal, the PCV seal (little rectangular seal, fairly sure that's what it is for), and the little sealing rings that the rocker cover bolts go through. ***PLEASE NOTE HERE*** that when you get your N14 metal rocker cover to get the bolts for it as well! They are a completely different length to the N15 cover; they are much shorter. You won't be able to use the N15 ones.

https://imgur.com/riblj7u
This picture shows the underside of the two covers next to each other. The one on the left is the N15 one whilst the one on the right is obviously the N14 one. As you can see, I have already pushed the new seals into the N14 rocker cover. I did this with a hammer, making sure to push the seal in as straight as I could with my fingers and then working my way around the seal with the hammer. You want them to sit flush, so if you can't achieve that with the hammer alone, use a suitably sized socket as a drift to push them in nice and even.

After this, I fitted the PCV rectangular seal, as can be seen in this photo.https://imgur.com/6fan4YX
This just pushed in. At this stage I also fitted up the rocker cover seal to the new rocker cover and put the sealing rings onto the bolts that hold it down; remembering that the metal part of the seal ring sits directly underneath the head of the bolt. I then set about removing the N15 rocker cover. I removed the bolts, starting from the middle and working my way outwards in a criss-cross fashion, and did the same upon reassembly. There are two hoses going into the rocker cover; one at the 'top' that goes into the PCV, and another one at the 'right' which goes to the air intake pipe. If the clamps are original, just use some pliers to squeeze these and move them back along the hose, and simply pull them off. Next I removed the spark plug leads. I didn't number these as they were still attached to the dizzy but may be worth doing so they don't get mixed up. After that, give the rocker cover a few hits with the palm of your hand to break the seal between it and the head, and lift it off. I gave the surface of the head (Where the rocker cover gasket sits) a bloody good clean, and then laid down a nice bead of RTV sealant and smoothed it out with my finger. I made sure to put a decent amount in the corners of the 'arch' of the head near the dizzy just in case. I grabbed the N14 rocker cover and went to put it on however noticed that it wouldn't sit on the head. This was because the spark plug tube seals were fouling on the tops of the tubes. I used a small flat head screwdriver to work each individual lip of the seal around the tube, so that the rocker cover could then sit on the head properly. From here, I installed each bolt and tightened them up in a criss-cross fashion as mentioned earlier; working my way out from the middle. I then re-fitted the spark plug leads and hoses going to the cover. A good thing with this is that there was no modifications required; the hoses went to the exact same locations on the rocker cover and there were no issues with hose length or inner/outer diameter at all.

https://imgur.com/SmRyC8i
So this is the finished product! All up it took maybe an hour, and that was going slowly. It really is an easy job, just a bit of a hassle that you need to go to a bit of effort (and cost) to replace something as simple as a few seals. The car is back to running as good as it used to now and that's the main thing!

I've probably explained this terribly, but if anyone does have any questions regarding this, I'm happy to explain further. Cheers!